A grandfather in Sydney’s west has had his $120,000 car stolen in front of him by a Facebook Marketplace thief.

Stephen Buttigieg was showing his collector’s edition Holden GTS to an apparent “interested buyer” on a Bonnyrigg Heights street.

The well-dressed man, who called himself “Brendon”, showed up on foot and was inspecting the car before sliding into the driver’s seat.

“He said, ‘I think your boot light’s coming on’, and I said, ‘Are you sure?'” Buttigieg said.

“And he said, ‘But it’s only when I put it in gear and reverse’, and the car was going forward and back a bit. So I said alright, I’ll check it.”

Security footage shows the man pop the boot and Buttigieg going to the rear of the car to close it, at which point “Brendon” sped off, leaving Buttigieg in shock.

“I just froze, and I couldn’t believe that he’d done that,” he said.

“Like he was such a nice person, he said he worked in a car yard, that he’s got money.”

The car was a parked nest egg: it was always locked away in a garage and had never been driven, and as a result it was not insured.

Buttigieg only hoped to sell the car as a way to help his sons buy their first home.

“People work hard, you try to help your kids, and this is what happens,” he said.

The thief has been reported to police, with detectives on the hunt for the suspect and the high-performance car.